gcc/
[official-gcc.git] / gcc / regstat.c
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1 /* Scanning of rtl for dataflow analysis.
2 Copyright (C) 2007-2016 Free Software Foundation, Inc.
3 Contributed by Kenneth Zadeck (zadeck@naturalbridge.com).
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
22 #include "config.h"
23 #include "system.h"
24 #include "coretypes.h"
25 #include "backend.h"
26 #include "rtl.h"
27 #include "predict.h"
28 #include "df.h"
29 #include "regs.h"
32 struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs;
34 /*----------------------------------------------------------------------------
35 REG_N_SETS and REG_N_REFS.
36 ----------------------------------------------------------------------------*/
38 /* If a pass need to change these values in some magical way or the
39 pass needs to have accurate values for these and is not using
40 incremental df scanning, then it should use REG_N_SETS and
41 REG_N_USES. If the pass is doing incremental scanning then it
42 should be getting the info from DF_REG_DEF_COUNT and
43 DF_REG_USE_COUNT. */
45 void
46 regstat_init_n_sets_and_refs (void)
48 unsigned int i;
49 unsigned int max_regno = max_reg_num ();
51 timevar_push (TV_REG_STATS);
52 df_grow_reg_info ();
53 gcc_assert (!regstat_n_sets_and_refs);
55 regstat_n_sets_and_refs = XNEWVEC (struct regstat_n_sets_and_refs_t, max_regno);
57 if (MAY_HAVE_DEBUG_INSNS)
58 for (i = 0; i < max_regno; i++)
60 int use_count;
61 df_ref use;
63 use_count = DF_REG_USE_COUNT (i);
64 for (use = DF_REG_USE_CHAIN (i); use; use = DF_REF_NEXT_REG (use))
65 if (DF_REF_INSN_INFO (use) && DEBUG_INSN_P (DF_REF_INSN (use)))
66 use_count--;
69 SET_REG_N_SETS (i, DF_REG_DEF_COUNT (i));
70 SET_REG_N_REFS (i, use_count + REG_N_SETS (i));
72 else
73 for (i = 0; i < max_regno; i++)
75 SET_REG_N_SETS (i, DF_REG_DEF_COUNT (i));
76 SET_REG_N_REFS (i, DF_REG_USE_COUNT (i) + REG_N_SETS (i));
78 timevar_pop (TV_REG_STATS);
83 /* Free the array that holds the REG_N_SETS and REG_N_REFS. */
85 void
86 regstat_free_n_sets_and_refs (void)
88 gcc_assert (regstat_n_sets_and_refs);
89 free (regstat_n_sets_and_refs);
90 regstat_n_sets_and_refs = NULL;
94 /*----------------------------------------------------------------------------
95 REGISTER INFORMATION
97 Process REG_N_DEATHS, REG_N_CALLS_CROSSED, and REG_BASIC_BLOCK.
99 ----------------------------------------------------------------------------*/
101 static bitmap setjmp_crosses;
102 struct reg_info_t *reg_info_p;
104 /* The number allocated elements of reg_info_p. */
105 size_t reg_info_p_size;
107 /* Compute register info: lifetime, bb, and number of defs and uses
108 for basic block BB. LIVE is a scratch bitvector used here. */
110 static void
111 regstat_bb_compute_ri (basic_block bb, bitmap live)
113 rtx_insn *insn;
114 df_ref def, use;
115 bitmap_iterator bi;
116 unsigned int regno;
118 bitmap_copy (live, df_get_live_out (bb));
120 /* Process the regs live at the end of the block. Mark them as
121 not local to any one basic block. */
122 EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi)
123 REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
125 /* Process the artificial defs and uses at the bottom of the block
126 to begin processing. */
127 FOR_EACH_ARTIFICIAL_DEF (def, bb->index)
128 if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0)
129 bitmap_clear_bit (live, DF_REF_REGNO (def));
131 FOR_EACH_ARTIFICIAL_USE (use, bb->index)
132 if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0)
134 regno = DF_REF_REGNO (use);
135 bitmap_set_bit (live, regno);
138 FOR_BB_INSNS_REVERSE (bb, insn)
140 struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
141 bitmap_iterator bi;
142 rtx link;
144 if (!NONDEBUG_INSN_P (insn))
145 continue;
147 link = REG_NOTES (insn);
148 while (link)
150 if (REG_NOTE_KIND (link) == REG_DEAD)
151 REG_N_DEATHS (REGNO (XEXP (link, 0)))++;
152 link = XEXP (link, 1);
155 /* Process the defs. */
156 if (CALL_P (insn))
158 bool set_jump = (find_reg_note (insn, REG_SETJMP, NULL) != NULL);
159 EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi)
161 REG_N_CALLS_CROSSED (regno)++;
163 /* We have a problem with any pseudoreg that lives
164 across the setjmp. ANSI says that if a user variable
165 does not change in value between the setjmp and the
166 longjmp, then the longjmp preserves it. This
167 includes longjmp from a place where the pseudo
168 appears dead. (In principle, the value still exists
169 if it is in scope.) If the pseudo goes in a hard
170 reg, some other value may occupy that hard reg where
171 this pseudo is dead, thus clobbering the pseudo.
172 Conclusion: such a pseudo must not go in a hard
173 reg. */
174 if (set_jump)
175 bitmap_set_bit (setjmp_crosses, regno);
179 /* All of the defs except the return value are some sort of
180 clobber. This code is for the return. */
181 FOR_EACH_INSN_INFO_DEF (def, insn_info)
183 if ((!CALL_P (insn))
184 || (!(DF_REF_FLAGS (def)
185 & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER))))
187 unsigned int dregno = DF_REF_REGNO (def);
189 /* Kill this register if it is not a subreg store or
190 conditional store.
191 ??? This means that any partial store is live from
192 the last use in a basic block to the start of this
193 basic block. */
194 if (!(DF_REF_FLAGS (def)
195 & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
196 bitmap_clear_bit (live, dregno);
198 if (dregno >= FIRST_PSEUDO_REGISTER)
200 REG_FREQ (dregno) += REG_FREQ_FROM_BB (bb);
201 REG_FREQ (dregno) =
202 MIN (REG_FREQ (dregno), REG_FREQ_MAX);
204 if (REG_BASIC_BLOCK (dregno) == REG_BLOCK_UNKNOWN)
205 REG_BASIC_BLOCK (dregno) = bb->index;
206 else if (REG_BASIC_BLOCK (dregno) != bb->index)
207 REG_BASIC_BLOCK (dregno) = REG_BLOCK_GLOBAL;
212 FOR_EACH_INSN_INFO_USE (use, insn_info)
214 unsigned int uregno = DF_REF_REGNO (use);
216 if (uregno >= FIRST_PSEUDO_REGISTER)
218 REG_FREQ (uregno) += REG_FREQ_FROM_BB (bb);
219 REG_FREQ (uregno) =
220 MIN (REG_FREQ (uregno), REG_FREQ_MAX);
222 if (REG_BASIC_BLOCK (uregno) == REG_BLOCK_UNKNOWN)
223 REG_BASIC_BLOCK (uregno) = bb->index;
224 else if (REG_BASIC_BLOCK (uregno) != bb->index)
225 REG_BASIC_BLOCK (uregno) = REG_BLOCK_GLOBAL;
232 /* Compute register info: lifetime, bb, and number of defs and uses. */
233 void
234 regstat_compute_ri (void)
236 basic_block bb;
237 bitmap live = BITMAP_ALLOC (&df_bitmap_obstack);
238 unsigned int regno;
239 bitmap_iterator bi;
241 /* Initialize everything. */
243 gcc_assert (!reg_info_p);
245 timevar_push (TV_REG_STATS);
246 setjmp_crosses = BITMAP_ALLOC (&df_bitmap_obstack);
247 max_regno = max_reg_num ();
248 reg_info_p_size = max_regno;
249 reg_info_p = XCNEWVEC (struct reg_info_t, max_regno);
251 FOR_EACH_BB_FN (bb, cfun)
253 regstat_bb_compute_ri (bb, live);
256 BITMAP_FREE (live);
258 /* See the setjmp comment in regstat_bb_compute_ri. */
259 EXECUTE_IF_SET_IN_BITMAP (setjmp_crosses, FIRST_PSEUDO_REGISTER, regno, bi)
261 REG_BASIC_BLOCK (regno) = REG_BLOCK_UNKNOWN;
264 timevar_pop (TV_REG_STATS);
268 /* Free all storage associated with the problem. */
270 void
271 regstat_free_ri (void)
273 gcc_assert (reg_info_p);
274 reg_info_p_size = 0;
275 free (reg_info_p);
276 reg_info_p = NULL;
278 BITMAP_FREE (setjmp_crosses);
282 /* Return a bitmap containing the set of registers that cross a setjmp.
283 The client should not change or delete this bitmap. */
285 bitmap
286 regstat_get_setjmp_crosses (void)
288 return setjmp_crosses;
291 /*----------------------------------------------------------------------------
292 Process REG_N_CALLS_CROSSED.
294 This is used by sched_deps. A good implementation of sched-deps
295 would really process the blocks directly rather than going through
296 lists of insns. If it did this, it could use the exact regs that
297 cross an individual call rather than using this info that merges
298 the info for all calls.
300 ----------------------------------------------------------------------------*/
304 /* Compute calls crossed for BB. Live is a scratch bitvector. */
306 static void
307 regstat_bb_compute_calls_crossed (unsigned int bb_index, bitmap live)
309 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
310 rtx_insn *insn;
311 df_ref def, use;
313 bitmap_copy (live, df_get_live_out (bb));
315 /* Process the artificial defs and uses at the bottom of the block
316 to begin processing. */
317 FOR_EACH_ARTIFICIAL_DEF (def, bb_index)
318 if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0)
319 bitmap_clear_bit (live, DF_REF_REGNO (def));
321 FOR_EACH_ARTIFICIAL_USE (use, bb_index)
322 if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0)
323 bitmap_set_bit (live, DF_REF_REGNO (use));
325 FOR_BB_INSNS_REVERSE (bb, insn)
327 struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
328 unsigned int regno;
330 if (!NONDEBUG_INSN_P (insn))
331 continue;
333 /* Process the defs. */
334 if (CALL_P (insn))
336 bitmap_iterator bi;
337 EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi)
339 REG_N_CALLS_CROSSED (regno)++;
343 /* All of the defs except the return value are some sort of
344 clobber. This code is for the return. */
345 FOR_EACH_INSN_INFO_DEF (def, insn_info)
347 if ((!CALL_P (insn))
348 || (!(DF_REF_FLAGS (def) & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER))))
350 /* Kill this register if it is not a subreg store or conditional store. */
351 if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
352 bitmap_clear_bit (live, DF_REF_REGNO (def));
356 FOR_EACH_INSN_INFO_USE (use, insn_info)
357 bitmap_set_bit (live, DF_REF_REGNO (use));
362 /* Compute register info: lifetime, bb, and number of defs and uses. */
363 void
364 regstat_compute_calls_crossed (void)
366 basic_block bb;
367 bitmap live = BITMAP_ALLOC (&df_bitmap_obstack);
369 /* Initialize everything. */
370 gcc_assert (!reg_info_p);
372 timevar_push (TV_REG_STATS);
373 max_regno = max_reg_num ();
374 reg_info_p_size = max_regno;
375 reg_info_p = XCNEWVEC (struct reg_info_t, max_regno);
377 FOR_EACH_BB_FN (bb, cfun)
379 regstat_bb_compute_calls_crossed (bb->index, live);
382 BITMAP_FREE (live);
383 timevar_pop (TV_REG_STATS);
387 /* Free all storage associated with the problem. */
389 void
390 regstat_free_calls_crossed (void)
392 gcc_assert (reg_info_p);
393 reg_info_p_size = 0;
394 free (reg_info_p);
395 reg_info_p = NULL;
398 /* Dump the register info to FILE. */
400 void
401 dump_reg_info (FILE *file)
403 unsigned int i, max = max_reg_num ();
404 if (reload_completed)
405 return;
407 if (reg_info_p_size < max)
408 max = reg_info_p_size;
410 fprintf (file, "%d registers.\n", max);
411 for (i = FIRST_PSEUDO_REGISTER; i < max; i++)
413 enum reg_class rclass, altclass;
415 if (regstat_n_sets_and_refs)
416 fprintf (file, "\nRegister %d used %d times",
417 i, REG_N_REFS (i));
418 else if (df)
419 fprintf (file, "\nRegister %d used %d times",
420 i, DF_REG_USE_COUNT (i) + DF_REG_DEF_COUNT (i));
422 if (REG_BASIC_BLOCK (i) >= NUM_FIXED_BLOCKS)
423 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
424 if (regstat_n_sets_and_refs)
425 fprintf (file, "; set %d time%s", REG_N_SETS (i),
426 (REG_N_SETS (i) == 1) ? "" : "s");
427 else if (df)
428 fprintf (file, "; set %d time%s", DF_REG_DEF_COUNT (i),
429 (DF_REG_DEF_COUNT (i) == 1) ? "" : "s");
430 if (regno_reg_rtx[i] != NULL && REG_USERVAR_P (regno_reg_rtx[i]))
431 fputs ("; user var", file);
432 if (REG_N_DEATHS (i) != 1)
433 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
434 if (REG_N_CALLS_CROSSED (i) == 1)
435 fputs ("; crosses 1 call", file);
436 else if (REG_N_CALLS_CROSSED (i))
437 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
438 if (regno_reg_rtx[i] != NULL
439 && PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
440 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
442 rclass = reg_preferred_class (i);
443 altclass = reg_alternate_class (i);
444 if (rclass != GENERAL_REGS || altclass != ALL_REGS)
446 if (altclass == ALL_REGS || rclass == ALL_REGS)
447 fprintf (file, "; pref %s", reg_class_names[(int) rclass]);
448 else if (altclass == NO_REGS)
449 fprintf (file, "; %s or none", reg_class_names[(int) rclass]);
450 else
451 fprintf (file, "; pref %s, else %s",
452 reg_class_names[(int) rclass],
453 reg_class_names[(int) altclass]);
456 if (regno_reg_rtx[i] != NULL && REG_POINTER (regno_reg_rtx[i]))
457 fputs ("; pointer", file);
458 fputs (".\n", file);